add new system file

hc

2024-02-20 102a0743326a03cd1a1202ceda21e175b7d3575c

 kernel/fs/eventfd.c
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@@ -187,11 +187,14 @@
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 	return events;
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 }
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-static void eventfd_ctx_do_read(struct eventfd_ctx *ctx, __u64 *cnt)
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+void eventfd_ctx_do_read(struct eventfd_ctx *ctx, __u64 *cnt)
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 {
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-	*cnt = (ctx->flags & EFD_SEMAPHORE) ? 1 : ctx->count;
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+	lockdep_assert_held(&ctx->wqh.lock);
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+
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+	*cnt = ((ctx->flags & EFD_SEMAPHORE) && ctx->count) ? 1 : ctx->count;
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 	ctx->count -= *cnt;
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 }
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+EXPORT_SYMBOL_GPL(eventfd_ctx_do_read);
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 /**
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  * eventfd_ctx_remove_wait_queue - Read the current counter and removes wait queue.